The purpose of the National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC) is to improve the diagnosis and management of patients receiving treatment for thoracic aortic aneurysms and dissections, which are known or suspected to be genetically induced, through the creation of a data and specimen repository. Data to be collected include medical, surgical, and lifestyle, as well as blood and tissue samples. RTI International will serve as the data coordinating center and prime contractor. The registry was designed and patient enrollment will be accomplished through the collaboration of five regional clinical centers (RCCs): Cornell University, Johns Hopkins University, University of Pennsylvania, Oregon Health Sciences University, and University of Texas at Houston. Approximately 3,000 patients will be enrolled, and data will be collected through medical record abstraction, physical examination, patient interview, and abstraction of other source records such as radiologic and echocardiography reports. Blood and tissue samples will be sent to the NHLBI biospecimen repository. A project website will serve as the portal for communications, data entry, data query, reporting, and dissemination of information. Secure pages will be available only to authorized users. A portion of the website will include public pages targeted to study subjects and outside investigators. Registry activities will be directed and monitored by the NHLBI and the Steering and Operations Committees through regular conference calls and in-person meetings. In addition, an NHLBI-appointed Observational Study Monitoring Board (OMSB) will perform independent monitoring of overall progress, clinical outcomes, and patient safety. The Registry includes a policy for sharing data and specimens that will permit Registry investigators and researchers outside the Registry to request these resources for research purposes.